It is well known for a data processing device to communicate with a user of the device by output of a string of alphanumeric characters. An example of such a device is a parcel processing system of the type disclosed in U.S. Pat. Nos. 5,024,282 and 5,009,276. A parcel processing system commonly includes a display by which alphanumeric prompt messages are output to guide the user in operation of the system. Such a system also frequently includes a printer through which the system outputs reports, parcel manifests and so forth. The reports usually comprise headings, subheadings, and/or page footers that are made up of strings of alphanumeric characters. The character strings making up the prompts, headings and other texts just described are typically stored in the system's memory and accessed as needed by the system's application program. Various methods of storing the strings have been used. For example, the strings may simply by embedded at appropriate places in the program code. It is also known to store the strings separately from the code and to generate a table that identifies the address at which each string is stored. The program then refers to the table when a particular string is required to be output.
It is also known to use strings of characters to control certain operations of a data processing device. For instance, a character string may comprise a "script" that provides format and other information required for generation of a report. A character string may also constitute a series of commands that controls an operating sequence or set up of the device.
Although prior art methods have been useful for their intended purposes, it is desirable to provide more flexible methods of storing and retrieving character strings, particularly in view of the need to make changes to output texts or control strings after the device has been placed at a user's location. Such changes may include correcting of errors, adding of new functions, changing report formats or adding new reports, or increasing the number of natural languages in which the device is able to communicate with the user.